1. Field of the Invention
The present invention relates to a cylindrical rotating tool, having internal fluid passage, which is attached to a machine tool to machine a workpiece, and a machining method using the tool.
2. Description of the Related Art
Japanese published patent No. 7-051982 describes a technology in which a tool or workpiece is cooled or lubricated by attaching a coolant nozzle to a rotating tool and by spraying coolant (cutting fluid) on a machining point of the tool from the coolant nozzle.
The rotating tool described in Japanese published patent No. 7-051982 may have the coolant nozzle attached thereto for spraying the coolant. A strong centrifugal force acts on the rotating tool, which is usually rotating at high speed (e.g., 2,000 to 10,000 min−1).
Therefore, it is difficult to supply sufficient coolant to an outer circumferential surface and the machining point of the tool from a place distant from the outer circumferential surface of the tool. In addition, it is necessary to attach the coolant nozzle to the tool as a separate component. As a result, the structure of the tool may become complicated and there is a risk that the separate component causes physical interference when moving the tool for tool change or machining.
As another background art, for example, end mills or drills among rotating tools may have an internal fluid passage formed therein for allowing the coolant to flow (Japanese published patent No. 2007-313574).
However, cooling effect has been low due to difficulty of sufficiently supplying the coolant ejected from the internal fluid passage to the outer circumferential surface of the tool and the machining point of a cutting edge.